Laterally movable railway vehicle truck

ABSTRACT

A railway vehicle comprises a bolster supported by each wheelset through a lateral suspension. The bolster is connected to the vehicle body to constrain it to move laterally with the bolster under centrifugal force by an amount related to the stiffness of said lateral suspension, but permitting lateral tilting of the body relatively to the bolster. Actuating means are provided to tilt the vehicle body relatively to said bolster through an angle related to the centrifugal force acting on the vehicle body, simultaneously with the lateral displacement of the body to counteract the effects of centrifugal force.

[56] References Cited UNITED STATES PATENTS Alan John Bing London,England Appl. No. 827,555 [22] Filed United States Patent [72] InventorX XXX 7 999 M HM 515551 0 000 l 111 951 Lynn et 937 Schoepfet al.

949 Dolan.............

950 Soloview 968 Bingham 969 Love May 26, 1969 [45] Patented Jan. 4,1972

[73] Assignee British Railway Board London, England [32] Priority May29, 1968 Primary Examiner-Arthur L. La Point Assistant ExaminerHowardBeltran AttorneySommers & Young Great Britain 25,847/68 w w mflma tr. ta t S t mm hm qn Wm 5 ub m n m m n e S v iia c TC t 3 0 3 am LT m U0 .m.a a e n l m b o m P e m $.W. e l w e mm mom SD i eu u wn y ABSTRACT: Arailway vehicle com by each wheel-set through a lateral connected to thevehicle body to constrain it to move lateral] with the bolster undercentrifugal force 105/171, t0 the stiffness of said lateral suspension,

tilting of the body relatively to the bol B61f 3/00, are provided totilt the vehicle bod B6 1f 5/24, B6lf 5/44 through an angle related tothe cen l05/l97, vehicle body, simultaneously with the 190 R, 210 thebody to counteract the effects of centrifugal force.

m H m M w R H .9. E m w W? v mm m H m Mn M W4 R M B F m m m m m Mm w m mm M m Y D m m mA .L 7 L m m m9 m n S1 .1 In h ECm C G o TUC M AR s m .w4 U U W r i 5 U PATENTEUJAN 4m SHEET 1 BF 4 Alan 70 m 71h Trader/ Mom ysPATENTEDJAN 4:972 3.631.810

SHEET 3 BF 4 FIG.7

PATENTEDJAN 41912 3.631.810

SHEET 0F 4 I nurln w LATERALLY MOVABLE RAILWAY VEHICLE TRUCK Thisinvention relates to railway vehicles, and more particularly, but notexclusively, to railway coaches for use in highspeed passenger trainscapable of speeds of upwards of 100 mph.

In designing a railway coach for use in highspeed passenger trainsrunning on existing tracks not designed for such high speeds, the effectof centrifugal force on the comfort of passengers arising fromdeficiencies in the cant of the track at curves when the trainnegotiates these curves at the designed high speeds, has to becounteracted and one way of doing this is to tilt the coach bodylaterally relatively to the wheelsets. For the comfort of passengers, itis desirable to tilt the coach body so that the resultant force on apassenger is perpendicular or nearly perpendicular to the coach floor.Ideally the coach body is therefore tilted so that the coach floor is atan angle to the plane of the track (hereafter tenned 0,,) equal to thecant deficiency; as will be appreciated the cant deficiency 0,, is afunction of the vehicle speed and the radius of the curve beingnegotiated by the vehicle. For optimum use of the space available withinthe loading gauge of the track, the tilt center about which the coachwill in effect be rotated will normally fall relatively high up withinthe coach body. To physically pivot the coach body on this tilt centerwould therefore require structure which intrudes into the passengerspace and this is very undesirable.

It is the object of this invention to provide a mechanism which willeffectively tilt the body about the aforementioned tilt center but whichis contained generally beneath the coach floor.

According to this invention there is provided a railway vehiclecomprising at least one wheelset disposed at each end thereof, a bolstersupported by said wheelset through a lateral suspension permitting thebolster to move laterally of the wheelset against a predeterminedstiffness of the lateral suspension, connecting means between saidbolster and the vehicle body constraining the vehicle body to movelaterally with the bolster whereby the body and bolster will bedisplaced laterally together under centrifugal force by an amountrelated to the stifiness of said lateral suspension, but permittinglateral tilting of said body relatively to said bolster, andservocontrolled actuating means arranged to tilt said vehicle bodyrelatively to said bolster through an angle related to the centrifugalforce simultaneously with the lateral displacement thereof, whereby theeffective tilt center of said body lies in the vertical centrallongitudinal plane of the vehicle and above the floor of the vehicle.

By the term bolster it is intended to include any appropriate form ofbeam or frame.

Thus it will be seen that the tilting arrangement of a railway vehicleaccording to the invention is advantageously combined with the lateralsuspension for the vehicle in a way permitting a soft lateral suspensionand low lateral unsprung mass.

In the case of a simple fourwheeled vehicle a bolster and tiltingactuating means will be provided at each wheelset. Similarly in the caseof a bogietype vehicle each bogie having two or three wheel-sets, a saidbolster and tilting actuating means will be provided at each bogie ofthe vehicle.

In the case where a pair of railway vehicles are interconnected by abeam articulated at its ends to the two vehicle bodies at a distancefrom the ends of said bodies the connecting means may be between saidbeam and a bolster on a single wheelset, or respective bolsters on apair of wheelsets each said wheel-set having tilting actuating means fora respective one of the vehicle bodies.

Advantageously said connecting means are arranged to effective tiltcenter of said body is spaced a distance d from said pivot givensubstantially by the expression d=Mg/Kk,, (where M is the mass of thebody and bolster and g is gravitational acceleration).

The invention will now be further explained with the air of theaccompanying diagrammatic drawings in which:

FIG. I shows diagrammatically one example of tilting system in theuntilted position,

FIG. 2 shows the system of FIG. I in a tilted position,

FIG. 3 shows diagrammatically a second example of tilting system in theuntilted position,

FIG. 4 shows the system of FIG. 3 in a tilted position,

FIG. 5 shows a diagrammatic plan view of one vehicle connected toanother vehicle in a train by a steering beam and in their relativeposition when negotiating a curve,

FIG. 6 is a perspective view of one example of construction of wheelsetand associated bolster frame, and

FIG. 7 is a diagrammatic view of the servocontrolled tilting actuator.

Referring now to FIGS. 1 and 2 these show the arrangement at onewheelset of a fourwheeled vehicle, the arrangement at the other wheelsetbeing similar. Chaindotted line 1 indicates the centerline of thewheelset axle on which the pair of wheels are mounted and which isrotatably supported in axle boxes. The vehicle has a bolster 2 extendingtransversely of the vehicle and pivotally mounted at its ends to thelower ends of swing links 3. The swing links 3 at their upper ends arepivotally mounted to a frame 4 mounted directly on the axle boxes of thewheelset. This provides a soft passive lateral suspension. The systemwill however work with any form of lateral suspension, whether employingpotential energy like swing links, or strain energy like simple springs.Thus the bolster 2 can swing relatively freely laterally of the vehicleand relatively to the wheelset under centrifugal force, but has nofreedom in roll. The vehicle body 5 is pivoted at P to a structuralmember 6 solidly mounted on the swinging bolster 2 and, by a similarpivot on a swinging bolster at the other wheelset but constraining it tomove laterally with the bolster 2. Tilting actuating means, in thisexample comprising hydraulic jacks 7 and 8, is provided for tilting thevehicle body about the pivot P by an amount related to the centrifugalforce acting as determined by an accelerometer mounted on the vehiclebody. The control of the tilting actuating system is described laterwith reference to FIG. 7.

The vertical central longitudinal plane of the vehicle is indicated bychain-dotted line 9 and the medial plane of the coach body bychaindotted line 10. The point 0 indicates the desired tilt center ofthe vehicle body in the vertical central longitudinal plane 9 and G thecenter of gravity of the vehicle body.

Referring now to FIG. 2, this shows the geometry of the system understeady curving conditions with a considerable cant deficiency 0 andtherefore with the vehicle body tilted through an angle 0,, about thedesired tilt center 0 by the tilting actuating means 7 and 8. Under thecentrifugal force MgO the bolster 2 will move laterally a distancePQ==Mg0 /k,, relative to the wheelset axle, where k, is the lateralsuspension stiffness. For correct tilting geometry, the point 0 must bewhere the medial plane of the tilted body 5 intersects the verticalcenterline of the axle, i.e. intersects the vertical centrallongitudinal plane of the vehicle, thus;

0P=PQlsin0 as 0,, is small, and substituting for PQ This applies to anyform of lateral suspension with linear stifi ness k, between the bolster2 and wheelset axle. With the cause said vehicle body to pivot on saidconnecting means, the swinglink form of lateral suspension shown in FIG.2 lateral lateral suspension means has a constant stiffness k, and saidactuating means tilt the body on said pivot and through an angle to thevertical k0 directly proportional to the centrifugal force acting (whereK is the constant of proportionality which may be greater than, equal toor less than unity) whereby the If the vertical and roll suspension issituated between the body and bolster 2 as shown diagrammatically inFIGS. 3 and 4 where the vertical and roll suspensions are represented byway of example as coils springs 12 in series with the hydraulic jacks 7and 8 between the coach body and the bolster, there is relative verticalmovement between the body and swinging bolster. The pivot P is thenreplaced by tie bar ll connected to the body 5 and member 6 at R and S.The bar 11 pennits this vertical roll movement but restrains lateralmovement between the swinging bolster and body.

One practical construction of the arrangement shown in FIGS. 3 and 4 isshown in FIGS. 6 and 7.

Referring now to FIG. 6 the wheelset axle is rotatably mounted in axleboxes provided in axle casing 4 and caries the pair of wheels 17. Theaxle casing 4 thus corresponds to frame 4 of FIGS. 3 and 4. The bolster2 is in the form of a rigid frame surrounding the wheelset and issuspended by the swing links 3 pivoted at their upper ends to yokes 4aon the axle casing 4. The hydraulic jacks 7 and 8 are duplicated and forconvenience have been given the suffix letters a and b. The body 5,represented by a longitudinal frame member (corresponding to steeringbeam 13 of FIG. 5, to be described), is connected to the bolster 2 bythe bar 11. The jacks 7a, 7b, 8a and 8b are combined with ahydropneumatic or hydromechanical system to provide vertical and rollsuspensions in the manner shown in FIG. 7. Obviously a wheel setarrangement as shown in FIG. 6 is provided at each end of the body 5.

Referring now to FIG. 7, this shows one simple form of tilting actuatingmeans adapted for use in the present invention, and corresponding instructure and operation to the accelerometer controlled fluid pumpingand jacking system shown and described in FIG. 5a of Bingham U.S. Pat.No. 3,376,830, issued Aug. 9, 1968, for Railway Vehicle SuspensionSystem." The hydraulic jacks 7 and 8, in FIG. 7 are double acting, i.e.they have working spaces l8, 19, 20 and 21 above and below their pistons22, the working space above each piston being connected to the workingspace below the other by connections 19 and 20'. The two connections 19'and 20' are themselves interconnected through hydraulic pump 21' whichis controlled by accelerometer 221. Thus in response to a tilting signalfrom the accelerometer 221 hydraulic fluid will be pumped from one pairof working spaces 18 and 21 into the other pair 19 and 20 and vice versadepending upon the direction of tilt required. This will cause thepistons to become disposed somewhat as shown in FIGS. 2 and 4.

Accumulators 23 may be pneumatic or mechanical spring devices and willthus provide vertical and roll suspensions equivalent to the springs 12shown in FIG. 4.

It may be desired that the vehicle body tilts to less than the cantdeficiency 0,,. If the required tilt angle is K6, and since the lateralmovement of the bolster is unchanged at Mga lky n u fl/K for theswinglink suspension OP is thus increased by the factor l/K.

FIG. 5 shows, in plan view, a train configuration in which a pair ofadjacent vehicles have their bodies 50 and Sb connected to each otherthrough a steering beam 13 which is articulatedly connected at its endson the centerlines of the two vehicle bodies 5 through vertical and rollpivots 14. The adjacent ends of the bodies 5 are jointed at in an mannerpermitting them to adopt the configuration when curving. The steeringbeam 13 is mounted to two wheelsets in substantially the same manner asthe vehicle body is mounted to the wheelset in FIG. 3, i.e., through atie bar, bolster and swinglinks. Thus the appropriate constructionalarrangement for the wheelset is shown in FIG. 6.

The hydraulic jacks 7a, 7b, 8a and 8b of one wheelset arrangement areconnected at their upper ends to the coach bodies, say 5a. The secondwheelset arrangement shown in FIG. 5 has its hydraulic jacks connectedat their upper ends to the coach body 5b. It will be appreciated thatthe two wheelsets shown in FlG. 5 could be replaced by a single wheelsetarrangement in which case the hydraulic acks of this single wheelsetwould connect with both coach bodies 50 and 5!).

For correct tilting the pivots R and S on the tie bar ll must bedisposed a distance Mg/K below the tilt center which, for the swing linksuspension shown, equates to [the length of the swinglinks. Thereforethe lateral connections from the bolster 2 to steering beam 13 to body 5should be a distance I below the tilt center.

In a modification of the systems described above, the simple pivotingarrangements between the bolster and body could be replaced by a linkagedesigned to produce a substantially rotational movement about thedesired pivot point which will in this case be an imaginary pivot point.This would be useful where the desired pivot point i.e., the actualcenter of rotation of the body movement, falls within the passengercarrying space of the vehicle body, because the linkage could bedisposed completely below the floor of the body.

I claim:

1. In combination, a railway vehicle comprising a vehicle body, at leastone wheelset, a vehicle suspension supporting said vehicle body on saidwheelset, said vehicle suspension including a lateral suspension ofsubstantially constant stiffness mounted on said wheelset for normallypositioning said body at a predetermined location relative to saidwheelset, a bolster connected to said lateral suspension for movementlaterally of the vehicle against the stiffness of said lateralsuspension, connecting means between said bolster and the vehicle bodyfor constraining the vehicle body and bolster to move together, inlateral directions away from said predetermined location, under theinfluence of centrifugal force acting on the vehicle body, a pivotincorporated in said connecting means to permit tilting of said bodyrelative to said bolster, means for providing a signal proportional tothe centrifugal force acting on the vehicle body, and actuating meansconnected between said body and said bolster, and responsive to saidsignal, for tilting said body relative to said bolster about said pivotthrough an angle directly proportional to the cen trifugalforce actingon the vehicle body.

2. The combination of claim 1 wherein said pivot comprises a simplepivot between said body and said connecting means.

3. The combination of claim 1 wherein said lateral suspension comprisesswinglinks.

4. The combination of claim I wherein the vehicle body is arranged forvertical and roll displacement relative to said bolster through verticalspringing positioned between the bolster and body, the tilting of thevehicle body being efiected through a tie bar pivotally connected at itsends to the vehicle body and bolster.

5. The combination of claim 1 wherein said connecting means comprises alinkage constraining the tilting of said vehicle body about an imaginarypivot point.

6. The combination of claim 1 wherein said actuating means compriseshydraulic jacks.

7. The combination of claim 1 wherein said actuating means compriseshydraulic jacks mounted in series with vertical springing between saidbody and said bolster.

8. The combination of claim 1 wherein a pair of said railway vehiclesare interconnected by a beam articulated at its ends to the two vehiclebodies at a distance from the ends of said vehicle bodies, saidconnecting means for each vehicle body being located between said beamand a bolster.

9. The combination of claim 8 wherein a single wheelset is provided onsaid beam.

10. The combination of claim 8 wherein a pair of said wheelsets areconnected to said beam through a pair of respective bolsters, therespective actuating means associated with each of said bolsters actingon a respective one of the bodies of said pair of railway vehicles.

1. In combination, a railway vehicle comprising a vehicle body, at leastone wheel-set, a vehicle suspension supporting said vehicle body on saidwheel-set, said vehicle suspension including a lateral suspension ofsubstantially constant stiffness mounted on said wheel-set for normallypositioning said body at a predetermined location relative to saidwheel-set, a bolster connected to said lateral suspension for movementlaterally of the vehicle against the stiffness of said lateralsuspension, connecting means betwEen said bolster and the vehicle bodyfor constraining the vehicle body and bolster to move together, inlateral directions away from said predetermined location, under theinfluence of centrifugal force acting on the vehicle body, a pivotincorporated in said connecting means to permit tilting of said bodyrelative to said bolster, means for providing a signal proportional tothe centrifugal force acting on the vehicle body, and actuating meansconnected between said body and said bolster, and responsive to saidsignal, for tilting said body relative to said bolster about said pivotthrough an angle directly proportional to the centrifugal force actingon the vehicle body.
 2. The combination of claim 1 wherein said pivotcomprises a simple pivot between said body and said connecting means. 3.The combination of claim 1 wherein said lateral suspension comprisesswing-links.
 4. The combination of claim 1 wherein the vehicle body isarranged for vertical and roll displacement relative to said bolsterthrough vertical springing positioned between the bolster and body, thetilting of the vehicle body being effected through a tie bar pivotallyconnected at its ends to the vehicle body and bolster.
 5. Thecombination of claim 1 wherein said connecting means comprises a linkageconstraining the tilting of said vehicle body about an imaginary pivotpoint.
 6. The combination of claim 1 wherein said actuating meanscomprises hydraulic jacks.
 7. The combination of claim 1 wherein saidactuating means comprises hydraulic jacks mounted in series withvertical springing between said body and said bolster.
 8. Thecombination of claim 1 wherein a pair of said railway vehicles areinterconnected by a beam articulated at its ends to the two vehiclebodies at a distance from the ends of said vehicle bodies, saidconnecting means for each vehicle body being located between said beamand a bolster.
 9. The combination of claim 8 wherein a single wheel-setis provided on said beam.
 10. The combination of claim 8 wherein a pairof said wheel-sets are connected to said beam through a pair ofrespective bolsters, the respective actuating means associated with eachof said bolsters acting on a respective one of the bodies of said pairof railway vehicles.